1. The problem statement, all variables and given/known data Use Gauss' law to find the charge density on a Van Der Graff dome (r=40cm) if it is charged to 100kV. What is the electric field strength at r=25cm? I understand gauss's law and I know that I need to use it to find the total charge enclosed on the dome. I can then work out the surface area of the dome and calculate charge density. If I define a gaussian surface to be a sphere outside the dome, I can work out the charge enclosed if i know the electric field at the gaussian surface. I figure I must use the 100kV given to find the field at the gaussian surface, but I don't understand how. Also, I need a little help with the second part of the problem. That radius given is inside the dome, unsure of where to go there. Thanks for any help.